Push button for radio apparatus



June 2, 1942. w. DOHSMANN Em 2,285,374

PUSH BUTTON FOR RADIO APPARATUS Filed April 8. 1941 m 1/ i2 73 I4 23 65 Q9 I l I, I I I x INVENTORS WERNER DOHSMANIV ALBRECH L YN BY 7 g ATTORNEY Patented June 2, 1942 PUSH BUTTON FOR. RADIO APPARATUS Werner Dohsmann and Albrecht Leyn, Berlin, Germany, 'assignors to Telefunken Gesellschaft fiir Drahtlose Telegraphic m. b. 11., Berlin, Germany, a corporation of Germany Application April 8, 1941, Serial No. 387,440

In Germany October 7, 1939 1 Claim.

In apparatus for radio telegraphy and telephony in order to switch-in a certain wave, or also for other purposes, it is known to employ push button switches. This push button control is used extensively, particularly in radio receivers, in which the tuning of the apparatus is carried out simply by pressing a push button assigned to the respective station.

The present invention relates to a special construction of these push buttons by which it is possible to see from a distance, or in the dark, the push button which happens to be depressed so as to recognize for instance on which wave the apparatus operates. The principle of the invention resides in that the push button knob is I made entirely, or in part, from a transparent material, for instance from glass, and that it; is so constructed and a source of light is so arranged in the apparatus that depending on whether or not the knob is depressed light falls thereon and this light illuminates the knob through reflection in the interior of the said knob.

The invention will be better understood in ref- -erence to the several figures, wherein Fig. 1 discloses the system according to the invention, Fig. 2 is a perspective, on an enlarged scale, of one of the push buttons, and Fig. 3 is an arrangement of several push buttons utilizing a single source of light. Referring to Fig. 1, I represents the push button consisting of a glass cylinder whose upper end, which is situated in the apparatus, is tapered or is provided with an oblique surface 2. Thereis connected to this oblique surface a part 3 consisting of opaque material and to which is connected the rod 4 which connects the switch or other operating mechanism. 5 is the wall or front panel of the apparatus and 6 is a source of light. Between the knob I and the source of light 6 there is positioned a screen 'I through whose opening 8 the light can fall upon the knob. In the position shown, the knob I is in its actuated condition, i. e. in the depressed state, and it is seen from the path of the light rays that the light falls through the side upon the knob, is reflected atthe tapered surface and leaves through the head of the knob. To the right of the bulb there is shown a corresponding knob which is not depressed. In this knob, I represents the glass body, 2' the taper or oblique surface, 3 the opaque part, 4' is the connection to the switch and I is the screen. As seen from the figure, the light in th s case falls upon the opaque part and not upon the transparent part, and the knob thus remains dark.

It is possible so to adapt the arrangement that several push buttons are illuminated in the same manner from a common source of light. It is then necessary that the tapered surfaces of the push button as regards the ray path which emanates fromthe source of light, have the same orientation. In Fig. 2, the transparent push button or part of the push button is shown in enlarged scale. I the cylindrical knob, 2 is the tapered surface acting as a mirror, and dotted line 9 represents the intersection line obtained when intersecting the surface 2 with a plane at right angle to the axis of the cylinder I at the center of this surface. This figure will serve to better understanding Fig. 3 which shows a plan view of five push buttons III, I I, I2, I3 and I4 which are illuminated from a common source of light 6. It can be seen from the indication of the path of the rays and from the intersection lines that the intersection surfaces of the individual push buttons are oriented in the same sense in respect to the source of light. The representations in Fig. 1 are meant to be solely special examples of construction. The basic idea of the present invention can be put into practice structurally in various ways. Thus, for example, and this point should be emphasized in particular, obviously a reversal of the construction is possible and eventually also suitable, namely a construction in which instead of illuminating the depressed knob, on the contrary the inactive knobs are illuminated. This may be of particular advantage where the tuning, or the setting is to be carried out in the dark. This would further require that the individual push buttons carry a special identification aside from the illumination, for instance station names or the initial letters of a station, or eventually a number. However the arrangement may also be such that the push buttons are illuminated in different colors and thus for instance a graduation for the various wave ranges may be provided.

What we claim is:

A push-button control system for radio apparatus comprising a panel and a plurality of aligned push-buttons which are reciprocable in the openings in the panel and each of which is adapted upon actuation from an inoperative to an operative position to control the adjustment of said apparatus, each push-button consisting of a solid transparent portion and a superimposed included in said radio apparatus and energized independently of the operation of the push-.

' buttons, the reflecting surfaces or the several push-buttons being. so orientated with respect to the light source that the light rays therefrom are directed towards said reflecting surfaces at substantially right angles thereto, and an apertured screen interposed in each of the paths between the light source and the several push-buttons,

the arrangement being such that in the operative 10 ALBRECHT LEYN. WERNER DOH SMANN. 

